CNN was first to report Friday that U.S. officials believe that Israel was behind the attack, which the network said was targeting the anti-ship missiles bound for Hezbollah in Lebanon.

A U.S. official told ABC News that it was unclear what kinds of weapons Israel may have been targeting in the July 5 airstrike.

Israeli officials have consistently declined to comment on previous reports this year that they have been responsible for airstrikes inside Syria.

The three previous covert Israeli air strikes that have taken place in Syria this year, confirmed afterwards by U.S. officials, all targeted Russian weapons systems that Syria was believed to be funneling to Hezbollah in Lebanon. Syria has been a long-time arms provider to the militant Lebanese organization.

The first strike near Damascus in late January targeted a convoy carrying anti-aircraft missiles that may have been on the move to Hezbollah.

In early May, Israel conducted two separate airstrikes, also near Damascus, that a U.S. official told ABC News targeted as many as a dozen medium range Fateh-110 missiles intended for Hezbollah.